The store button in the Audible app (left) and the new version acknowledging the removal of the button to comply with Apple’s rules (right).

UPDATE: [Monday, October 10, 2011 at 12:40am ET]: Well, that sure was quick. A new version of the Audible app has just gone live on the App Store, without the link to Audible’s Mobile Store from the app. The development actually means someone at Apple’s App Store team messed up. We’re still bewildered how anyone could have missed the big orange button.

Back this summer, Apple instituted a change to the App Store rules which prohibited in-app links leading to external content stores. The controversial move forced the makers of programs such as WSJ, Kobo and Google Books to remove the offending store links, which essentially meant demanding users needed to find out about web stores on their own. People had been especially concerned about Amazon, even after the online retailer released an elegant workaround solution, a web-based application entitled Kindle Cloud Reader. And now, ZDNetdiscovers an interesting anomaly in the App Store: the updated Audible app proudly sports a button which yanks you out of the app right to their store on the web.

It could be a slip up by the App Store review team, but how could that be possible with such a large and prominently placed button? Oddly enough, release notes fail to acknowledge the addition of the button, but surely Apple’s testers actually run and test apps rather than approve them based on their iTunes description. What’s interesting about this is that Audible is an Amazon property. Perhaps this signals a store-wide change to the App Store rules. And if so, could this change be due to Amazon’s $199 seven-inch Kindle Fire tablet?

If it’s not a change of heart, then it’s entirely possible Audible simply agreed to sharing 30 percent on revenues generated from sales on audible.com coming from the in-app link. You could ask yourself who in their right mind would do that, but remember that Audible has been a long-time iTunes partner providing audio books for Apple’s content store.